The research to be conducted during the coming year (1974) of the grant will focus primarily on two interrelated questions: (1) what are the properties of a stimulus that heighten its capacity to evoke impulsive aggressive reactions, and (2) under what conditions will an attack lead to still more, rather than less, aggression towards the victim? In regard to the first problem, we will investigate a particular stimulus' associations with prior reinforcements for aggression. The second problem will be concerned with the aggressor's goals and intentions and his notions of equity.